But Shirley claims sentences were lifted without attribution in the book almost word for word.

For instance, page 287 of Shirley’s “Reagan’s Revolution” states: “Even its ‘red light’ district was festooned with red, white, and blue bunting, as dancing elephants were placed in the windows of several smut peddlers.”

Page 771 of “The Invisible Bridge” says: “The city’s anemic red-light district was festooned with red, white and blue bunting; several of the smut peddlers featured dancers in elephant costume in their windows.”

A lawyer representing Shirley sent a letter to Simon & Schuster seeking redress, but the publisher is standing behind Perlstein and his book.

“We have examined Mr. Shirley’s claims, found them to be entirely without merit, and responded to him accordingly,” S&S spokesman Cary Goldstein told me. “In ‘The Invisible Bridge,’ Rick Perlstein, an acclaimed and award-winning historian and author, has written an 800-plus page masterwork that draws upon hundreds of sources, all of which are amply credited in more than 4,000 citations.

“Making this claim even more absurd, these citations are readily available for one and all to see on Mr. Perlstein’s Web site, where Shirley’s work alone is credited more than 100 times, and with links to the relevant passages where available.”